IEEE Std 4003 pdf download IEEE Standard for Spaceborne Global Navigaton Satellite System-Refectometry (GNSS-R) Data and Metadata Content 3.2 Fundamental observables The collection of fundamental observables shall include the complete characterization of the following terms: ddm_complex: This feld includes the after-correlation in-phase I (real part) and quadrature Q (imaginary part) components of the scattered signal in raw counts. GNSS-R sensors...